1. Field of the Invention
This invention relates to a composite, tamper resistant, radiation sensitive device for instantly monitoring a high dose of high-energy radiations, such as electrons, X-rays, protons, alpha particles and neutrons using color-changing materials and methods of making and using same.
2. Brief Description of Prior Art
Patent application number WO 2004/077097 (U.S. Ser. No. 10/524,096 filed Feb. 4, 2005) which is incorporated herein by reference, describes a radiation sensitive dosimeter. The radiation sensitive dosimeter is typically made by sandwiching a radiation sensitive coating or strip between two plastic layers with a pressure sensitive adhesive. These radiation sensitive dosimeters are referred herein to as SIRAD for Self-indicating, Instant, Radiation Alert Dosimeter. However, these SIRAD badges are not tamper resistant because of the adhesive layer.
Radiation sensitive materials, such as diacetylenes (R—C═C—C═C—R, where R is a monovalent group) and processes that can be used for making radiation sensitive coatings or strips for making SIRAD are listed in patent application number WO 2004/077097 and WO 2004/017095 (U.S. Ser. No. 10/545,796, filed Jul. 6, 2006 and Ser. No. 10/524,096, filed Sep. 25, 2005 respectively) incorporated herein by reference and references cited therein. Coatings, films or plaques of radiation sensitive materials which are used to make SIRAD are individually or collectively, referred herein to as “radiation monitoring component”, “radiation sensitive coating”, “radiation sensitive strip” or “SIRAD strip”. Additives, such as UV absorbers that can be used in the present inventions are also listed in patent application number WO 2004/077097 and WO 2004/017095 and references cited therein.
Smart cards are typically one composite pieces of plastic. It is almost impossible to access the encapsulated electronic components of smart cards without cutting the cards. Smarts cards are typically tamper resistant and evident. To the best of our knowledge, there has been no report of a radiation sensitive smart card.
Smart cards are used as bankcards, ID cards, telephone cards and the like. Smart cards are usually made by embedding electronic components between several layers of plastic sheets in a sandwich array. If the electronic components can withstand high temperature, smart cards are made by encapsulating them in molten polymeric materials. Recently smarts cards have been made by encapsulating electronic components in polymeric materials by a technique commonly known as reaction injection molding.
U.S. Pat. No. 6,241,153 to Tiffany, III; Harry J. and U.S. Pat. No. 6,256,873 to Tiffany, III; Harry J. describe methods of making smart cards having high quality external surfaces by making use of a primer/adhesive (and, optionally, anchor hooks) on the lower surface of an electrical component in order to affix said electrical component to a thermosetting material that becomes the core layer of said cards.
European patent 350179 to Arvis; Charles Richard discloses a smart card wherein electronic circuitry is encapsulated in a layer of a reaction moldable polymeric material that is introduced between the card's two surface layers. Similarly European Patent Application 95400365.3 teaches a method for making contactless smart cards where an electronic module is encapsulated with a polymerizable resin material between upper and lower thermoplastic sheets.
U.S. Pat. No. 5,399,847 to Droz; Francois teaches a credit card that is comprised of three layers, namely, a first outer layer, a second outer layer and an intermediate layer. The intermediate layer is formed by injecting a thermoplastic binding material that encases the electronic elements in the intermediate layer material. The binding material is made of a blend of copolyamides or a glue having two or more chemically reactive components that harden upon contact with air. The outer layers of this smart card can be made up of various polymeric materials such as polyvinyl chloride or polyurethane.
U.S. Pat. No. 5,417,905 to Lemaire; Gerard and Lemaire; Philippe teaches a method for manufacturing plastic credit cards wherein a mold tool comprised of two shells is closed to define a cavity for producing such cards. A label or image support is placed in each mold shell.
Making of smart cards is also disclosed in other patents including U.S. Pat. Nos. 4,339,407, 4,961,893, 5,350,553, 5,423,705, 5,498,388 and 5,510,074. All of these prior art methods for making smart cards are usually for encapsulating electronic components or circuitry inside the smart card. Often the electronic components are held in place with a glue sometimes isotropic thermoset adhesive materials.
We have discovered that tamper resistant SIRAD can be made by encapsulating radiation sensitive coating or strip in a polymeric material. Tamper resistant smart SIRAD cards are also referred herein to as tamper resistant SIRAD or TR-SIRAD.
The core polymeric materials that can be used for making tamper resistant SIRAD badges are well known in the art. They are usually monomeric and oligomeric materials and polymerized and/or crosslinked with a catalyst for fast polymerization. Monomers, oligomers and crosslinkable polymers are referred to as pre-polymers. Monomers, oligomers and polymer that can be used to make tamper resistant SIRAD cards are also listed in patent application number WO 2004/017095.
Essentially any regular or irregularly shaped article can be produced by molding, i.e., injecting a molten polymer in to a mold. Thick film, plaques and blocks of a variety of plastics are also routinely casted from their monomers or oligomers, such as acrylics, urethane and epoxy followed by their polymerization. For example, (1) an epoxy polymer can be prepared by reacting an epoxide, preferably an oligomeric epoxide with a primary amine or a diepoxide with a di-secondary amine, and (2) a polyurethane/polyurea can be prepared by reacting a diisocyanate, preferably an oligomeric, with a diol or diamine, preferably an oligomeric diol or diamine. By selecting a proper molecular weight and nature of the amines or other catalysts, one can control the rate of polymerization or curing. These non-diacetylenic monomers and oligomers are referred to hereafter as core materials or core layer(s).